1. Field of the Invention
The invention relates to a counting chamber for optical detection of particles that are present in a fluid, comprising two substantially transparent and substantially parallel plates of material, between which the fluid can be introduced, wherein at least one of said plates includes a visible reference.
2. Description of the Related Art
Such counting chambers can be used for examining blood, urine or sperm and all other fluids.
The term reference is understood to means a visible image, in particular an image which visibly delimits parts of the counting chamber when a person is viewing the counting chamber through a microscope. The particles that are present in the fluid can be quantified in that case by counting or estimating the number of particles that are present in a specific delimited section.
The reference can also be a gauge, which is divided into units of length, so that it is possible to determine the size of the particles that are present in the fluid.
It is important that the reference, or the image, consists of lines which reduce the visibility of the fluid to a minimum degree. It is possible to use extremely thin lines for that purpose, but such lines are difficult to place and, in addition, they do not show up very well at all times.
The object of the invention is to provide a counting chamber including a reference which reduces the degree of visibility in the counting chamber only slightly, and which is nevertheless readily perceptible to the eye.
Another object of the invention is to provide a counting chamber which meets the necessary quality requirements, and which can nevertheless be manufactured at low cost. For hygienic reasons, single use is strongly preferred.